New Device to Measure Cross-Sectional Areas and Segmental Volumes of Objects and Limbs

Purpose: High accuracy volume measurements have important implications in different medical and non-medical situations. All methods used to date have challenges to achieve a usable clinical accuracy. Moreover, current methods have limitations to measure segmental volumes. We developed a new device that is able to measure a continuous profile of the cross-sectional areas along an object. Herewith the total volume of an object or any part of it are correspondingly determined. Methods: The Peracutus Aqua Meth (PAM) generates continuous profiles of cross-sectional areas. Water is pumped in or out of a measuring unit at a nearly fixed flow rate and the speed of the water level (dh/dt) is measured continuously using a pressure sensor at the bottom. The change of the water level is a measure for the cross-sectional area of an object at any height. Signal processing is required to obtain valuable measurements. Three static objects and an arm of a test object were measured to demonstrate the accuracy and repeatability of the new device. Results: Cross-sectional areas of a PVC pipe obtained with the PAM and with a caliper were compared. The differences between the two methods were less than 1.3%. Volume measurements of two mannequin arms show standard deviations of 0.37% and 0.34%, respectively, whereas the standard deviation of the volume measurement of a genuine arm was only 1.07%. These figures surpass reported clinical accuracy. Conclusion: The new device demonstrates that determining the cross-section and its volumes of objects is possible in an accurate, reliable, and objective way. The results show that segmental volume measurements of human limbs are possible. Application in clinical and non-clinical situations seems meaningful.